Find "Change password"
Press the Navigation key.
Scroll to Settings and press the Navigation key.
Scroll to Applications and press the Navigation key.
Scroll to Call and press the Navigation key.
Scroll to Voice calls and press the Navigation key.
Scroll to Call barring and press the Navigation key.
Press Options.
Scroll to Change password and press the Navigation key.
Change barring password
Key in your current barring password (default is 0000) and press the Navigation key.
Key in the required barring password and press the Navigation key.
Key in the barring password again and press the Navigation key.
Exit
Press Disconnect to return to standby mode.